The Advanced Intelligent Network (AIN) provides centralized control of telephone services provided to subscribers through diversely located central office switching systems. In an AIN type system, central offices send and receive data messages from an Intelligent Services Control Point (ISCP) via a Switching Transfer Point (STP). At least some calls are then controlled through multiple central office switches using data retrieved from a data base in the ISCP. In recent years, a number of new service features have been provided by the Advanced Intelligent Network (AIN).
U.S. Pat. No. 4,756,020 issued Jul. 5, 1988, to Joseph V. Fodale, for example, suggests access authorization in a multiple office environment. The Fodale system restricts access to a long distance telephone network based on the status of the billing number associated with the call, i.e. delinquent. The access control is provided through multiple local and toll offices but is centrally controlled by a data base which stores account status information. The local office serving a calling telephone extends a toll call to the toll office of the toll network carrier. The toll office queries the data base via a CCIS link regarding the current status of the customer's account identified by the billing number associated with the call. The data base obtains the status information of the billing number in question and translates that status into a response message instruction to allow or disallow extension of the toll call through the toll network. The data base transmits the response message to the toll office via CCIS link, and the toll office disallows or extends the call through the toll network as instructed by the response message.
A number of the features provided by the prior art AIN type intelligent networks relate to specialized call processing of incoming calls, as discussed below.
U.S. Pat. No. 4,191,860 issued Mar. 4, 1980, to Roy P. Weber discloses a system for providing special processing of incoming calls via a number of local switching offices based on information stored in a central data base. The local and toll offices of the telephone network compile a call data message and forward that message via a CCIS link to the central data base, essentially a Service Control Point or SCP. The data base at the SCP translates the dialed INWATS number, included in the message, into a call control message. The call control message includes an unlisted destination telephone number, which is then returned to the offices of the network via CCIS link. The network uses the call control message to complete the particular call.
U.S. Pat. Nos. 4,611,094 and 4,611,096 both to Asmuth et al. disclose a system for providing custom incoming telephone call processing services to a corporate customer operating at geographically dispersed locations through a plurality of local office switches. A customer program stored in a central data base is accessed to provide instructions to the switches to complete incoming calls to customer locations in accord with special services defined by the corporate customer. Incoming calls to the customer are routed to an Action Control Point (ACP) which typically is a modified toll office. The ACP has a number of "primitive" call processing capabilities, such as providing voice prompts to callers and receiving additional caller inputs. The customer program controls the ACP's to string together the desired primitive call processing capabilities to process each call to the customer. Specified parameters stored in the program, such as time of day, caller location and data inputs responsive to the voice prompts, determine the final customer station to which each call should be completed. The customized call processing disclosed by Asmuth et al. can also include customized billing for calls, e.g, by splitting charges between the customer and the caller. The Asmuth et al. system sets up a billing record for each call in the ACP or toll office. Asmuth et al. also teach procedures for handling of calls directed to a corporate customer when the call serving office does not have all of the capabilities needed for processing the call in accord with the customer's stored program. In particular, upon recognition of the deficiencies of the call serving office, the Asmuth et al. system transfers call processing to a second office having adequate capabilities for completion of the call.
U.S. Pat. No. 4,788,718 issued Nov. 29, 1988, to Sandra D. McNabb et al. suggests centralized recording of call traffic information. The architecture is similar to that disclosed by the earlier discussed patents to Weber and Asmuth et al. to the extent that local and toll offices communicate with a central data base via CCIS link. The McNabb et al. system improves over the incoming call routing provided by the Weber patent and the two Asmuth et al. patents discussed above by adding a data gathering function to the centralized data base which stores the individual customer's call routing program. In McNabb et al. the central data processor provides call attempt records and a traffic data summary of all calls directed to a particular 800 number.
U.S. Pat. No. 4,757,267 issued Jul. 12, 1988, to Bernard J. Riskin teaches routing of an 800 number call, where the dialed number identifies a particular product or service, to the nearest dealer for the identified product or service. The toll office sends a message including the dialed 800 number and the area code of the caller to a data base which translates this into a standard ten digit telephone number for the nearest computer at a Customer/Dealer Service Company (CDSC). The telephone network then routes the call to this computer, which answers the call and provides a synthesized voice response. The computer uses call data and or Touchtone dialed information from the caller to identify the selected product or service and then accesses its own data base to find the telephone number of one or more nearby dealers in that product or service. The computer then calls the dealer and connects the original caller to the called dealer.
Several other patents use a network similar to the AIN type intelligent network to provide personalized services to individual subscribers, for example when they are away from their home telephone station.
U.S. Pat. No. 4,313,035 issued Jan. 26, 1982, to David S. Jordan et al. patent discloses a method of providing a person locator service through multiple exchanges of the switched telephone network. Each subscriber is assigned a personal number uniquely identifying the subscriber. An absent subscriber inputs a number to which calls are to be completed, such as the number where the subscriber can be reached, into a central data base. A caller wishing to reach the subscriber dials the number uniquely identifying that subscriber. In response to an incoming call directed to the unique number, a telephone switching office having access to CCIS sends the dialed number to the central data base referred to by Jordan et al. as an SSP. The data base retrieves the stored completion number for the called subscriber and forwards that number back to the switching office to complete the call. The subscriber can update the stored data from any telephone. Also, the subscriber can specify whether to charge calls via the person locator system to the subscriber or to the caller.
U.S. Pat. No. 4,899,373 issued Feb. 6, 1990, to Chinmei Lee et al. discloses a system for providing special telephone services to a customer on a personal basis, when the customer is away form his or her home base or office. A nationally accessible data base system stores feature data in association with personal identification numbers. A subscriber wishing to use personalized features while away from home base dials a special code from a station connected to any exchange which has access to the data base and presents the personal identification number. The corresponding feature data is retrieved from the data base and stored in the exchange in association with the station from which the request was initiated. The exchange then provides telephone service corresponding to the subscriber's personalized telephone features. A temporary office arrangement may be established in which the personalized features will be immediately available on incoming and outgoing calls for a period of time specified by the subscriber.
Further modifications of the AIN system allow a TELCO to customize the routing of telephone calls via a graphical programming language used on a specialized terminal by telephone company personnel.
As seen from the cited patents, the prior art AIN systems are exclusively land line communications systems, i.e. they provide telephone communication services via wired telephone lines, which to the subscriber typically is a tip and ring pair. The signalling protocol used for AIN allows only for control of telephone network switching elements in response to queries originated by network switching elements. Wired line communications, even those provided by AIN, are necessarily limited by the fixed nature of installed lines. These systems make no provision for communication to any mobile unit.
Separate radio-link communications systems have been developed which generally relied on the TELCO's only to provide trunks and voice communication to and from land line based parties. Operation of the mobility controllers of the mobile or radio network has been controlled entirely within the radio-link communication network.
The most common type of mobile radio link communication systems is the cellular radio telecommunications system (cellular telephone or mobile telephone system). The cellular telecommunications industry has developed roaming standards which when implemented will allow automatic handoffs from one cellular network to another during an established call, and to allow roaming from one system to another while having incoming calls follow the customer to the visited system. The protocol which accomplishes this are set out in the EIA/TIA publications IS-41.1-A, IS-41.2-A, IS-41.3-A, IS-41.4-A, and IS-41.5-A. For example, in all cellular systems conforming to IS-41 Rev. a. registration of an activated roaming mobile station takes place automatically even if a call is not in progress or being requested. The IS-41 protocol is an out-of-band signalling protocol which may be transported by either X.25 or SS#7 links. No links to the land line network, however, have previously been established for IS-41 signalling.
The link between the mobile cellular user (CSS) and the appropriate base station (BS) uses particular radio frequencies mandated by the FCC. Dedicated trunk lines serve as the link between the base station and the mobile switching center (MSC), and the interface between mobile switching centers within the same system (same cellular provider) is generally provided by dedicated land lines. Data links connect the mobile switching center to a visitor location register (VLR), home location register (HLR), and equipment identity register (EIR), all of which can be located at the mobile switching center or at a remote point. All three registers may serve more than one mobile switching center. The HLR is the location register to which a user identity is assigned for record purposes, such as subscriber information, i.e., directory number, profile information, current location, validation period. The VLR is the location register, other than the HLR, which an MSC temporarily uses to store and retrieve information regarding a visiting subscriber or user. The differences between the VLR and the HLR are moot when handoff of a mobile user or subscriber is limited to the MSCs within a single system (single provider), since all the users are presumed to be listed in the home location register, and are validated on that basis. The VLR becomes important only when a subscriber who is not listed on the HLR of a cellular provider enters the system and registers. This situation is commonly described as roaming.
After determining that a roaming subscriber is currently within its surface area, the serving MSC sends a REGNOT (registration notification) to its VLR. The new serving MSC may detect a roaming subscriber's presence through automatic autonomous registration without a call request, call origination, call termination (such as a page response following a call to the roamer port), or a service order. If the roaming subscriber had previously registered with an MSC within the domain of the VLR, the VLR may take no further action other than to record the identity of the MSC currently serving the roaming subscriber. If the roaming subscriber was previously unknown to the VLR, or if the MSC registered information not available at the VLR, the VLR sends an REGNOT signal to the HLR associated with the roaming subscriber. The MSC recognizes this association based on the mobile identification number (MIN) reported by the roaming subscriber's mobil communication unit upon entering the new service area. The REGNOT signal sent from the VLR to the MSC may be contingent upon the response received from the HLR. For example, the roaming subscriber may not currently be a valid subscriber of the system in which the HLR is located.
If the roaming subscriber was previously registered elsewhere, the HLR sends a REGCANC (registration cancellation) signal to the previously visited VLR. That VLR (old serving system), upon receipt of the cancellation message, essentially removes all record of the roaming subscriber from its memory. The REGCANC signal can be sent by the HLR at any time after it receives the REGNOT signal. The new serving VLR creates an entry for the roaming subscriber in its internal data structure and may send a QUALREQ (qualification request) signal to the HLR in order to authenticate the roaming subscriber and determine the validation requirements. The VLR, if required, may then send a PROFREQ (service profile request) signal to the HLR to obtain the service profile for the roaming subscriber.
Many mobility controllers of the above described cellular systems are now programmed to provide subscribers selected special services. Normally, roaming subscribers engaged in "feature calls" which require special support by the system will not be handed off between systems. If the mobile subscriber has roamed to another system and registered on that system, normally the special features will not necessarily be allowed to the roamer. Normally handoff of a roaming subscriber in the "on-hook" state (not engaged in a call) will not take place when moving to a new system. Further, path minimization which is often found in the control scheme of a single system may not be provided for when a handoff of a roaming user from one system to another occurs. Thus, special services or features available to a subscriber through the home system are not available when the subscriber roams through other systems.
Data networks, such as X.25 packet switched networks, interconnect the mobility controllers with each other for data communications, for example to transfer necessary data from a subscriber's HLR to a VLR in the mobility controller the subscriber's mobile station is currently communicating with. The IS-41 protocols used by the mobile communications networks, however, have not been compatible with the protocols used to communicate between SSP's and the ISCP of the land based Advanced Intelligent Network.
There have been efforts to interface the two kinds of telephone device to provide unbroken access to at least one communication system at all times. One such arrangement is the well known cordless telephone. This telephone includes both a handset having a radio transceiver and a base station having a transceiver. The base unit connects to a land line system. A DTMF dialer in the base responds to control signals received through the base station transceiver to request telephone services, e.g., place a call. When an outgoing call is desired, a data stream is output from the handset over a radio link to the base station, initiating an interrogation routine in which the identity of the handset (usually required or programmed into a handset microprocessor) is confirmed at the base station. The desired telephone number is punched into a key set on the handset and output as a data stream. This data stream is received by the base unit and converted for use on the land line telephone system as DTMF signals.
Typically, both handset and base station include a microprocessor to control operations thereof. These operations include a registration between the handset and the base station before the base station will establish communication with the land line.
Registration can occur automatically when a handset enters the area of a base station. Alternatively, the registration between handset and base unit can occur when an incoming land line call is received by the base station or when the user seeks to make an outgoing call.
Since cordless telephones are generally controlled by microprocessors, a wide variety of functions such as intercom, three-way conversations, memory dialing, answering machine functions, and timed-automatic dial-out, are available. Also, since the base unit connects to a standard telephone, telephone network special services, such as those provided by AIN, are available to the handset via its associated base unit. Cordless handsets, however, use very little power and consequently have a very limited range with respect to the base station and consequently have limited range. Also, cordless telephone systems generally operate at different frequencies than those used by cellular telephone systems or microcell systems so that the cordless set cannot roam through the cellular network.
An essential problem with all of these systems is that they are not universal. Some environments require the use of one kind of system while precluding the use of others. For example, a moving vehicle requires the use of a cellular system and precludes the use of a direct land line connection. The expense of a cellular system, however, makes the use of a fixed land line far more practical when the user is at a stationary location. Even at a stationary location, such as one's home, a user cannot remain constantly within earshot of a telephone. Consequently, the use of a cordless handset system becomes necessary to one who wishes to move about while maintaining access to a communications system. Since the cordless telephone system does not interface with the cellular telephone system, the user much switch systems when changing environments, entailing an interruption of access to communications systems and requiring additional costly equipment as well as necessitating the use of an additional telephone number. Further, special features available and often relied upon in one system are often not transferrable to another system. Consequently, the user must readjust his mode of communicating to compensate for changes in the features available on each type of communication system.
From the above discussion, it becomes clear that the AIN provides one set of services to land line customers and the mobile communication system provides a different independent set of services. A subscriber wanting access to both types of services had to subscribe to both and typically was assigned two independent numbers, i.e. telephone numbers, at which to receive calls via each network. Such dual independent subscription increased costs to the subscriber and made it difficult for callers to know which number to use to currently reach the subscriber. Also, the wide variety of service features available to the subscriber via the AIN were not readily available to the subscriber via the mobile communication network, and those special service features available to the mobile subscriber were available only to the home cellular system.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.